Implantable medical devices (IMDs) are devices designed to be implanted into a patient. Some examples of these devices include cardiac rhythm management devices such as implantable pacemakers and implantable cardioverter defibrillators (ICDs). The devices are used to treat patients using electrical therapy and to aid a physician or caregiver in patient diagnosis through internal monitoring of a patient's condition. The devices may include electrical leads in communication with sense amplifiers to monitor electrical heart activity within a patient, and often include sensors to monitor other internal patient parameters. Some IMDs are able to provide both anti-tachyarrhythmia pacing (ATP) and defibrillation shock therapy. When tachyarrhythmia is detected, the device may first try to convert the arrhythmia with ATP before resorting to high energy defibrillation. If conversion is successful, ATP spares the patient from the pain of a high energy defibrillation shock. However, tachyarrhythmia can quickly degenerate into a life threatening condition. Therefore, it is necessary to provide an appropriate therapy as quickly as possible.